Reduction of FXI plasma activity and elevation of APTT following ISIS 416858 treatment. Cynomologus monkeys were administered ISIS 416858 (0 or 20 mg/kg/wk, SC) for up to 6 weeks. Blood was harvested for assessment of (A) FXI plasma activity or (B) PT and APTT at several time points following treatment initiation. Data represents mean ± SD. *Statistical difference from the control group (P < .05).